Chemical depth profile of ultrathin nitrided SiO2 films

Ultrathin nitrided SiO2/Si(001) films were studied using angle-resolved x-ray photoemission spectroscopy. The structure of the oxynitride depended on the nitridation process. Under one type of nitridation the film kept the structure of the SiO2, with N assuming O sites. By taking advantage of the nonuniformity on the chemical depth profile, the Si 2p chemical shift was determined for those Si atoms bonded to three O and one N atom, and for those bonded to two O and two N atoms. The stoichiometry depth profile was recognized through a simple method that allowed the input of physical constrains. (C) 2002 American Institute of Physics.